EPA’s Hierarchy of Preferred Disposal

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The oil and gas industry has multiple options for disposing of the byproducts of operations; however, some options are much better than others. The EPA created a hierarchy of preferred waste management options to help industries gauge their current practices as they work towards more sustainable practices.

More EPA Hierarchy Info

Source Reduction and Reuse

Source reduction and reuse is the most preferred method because it can save natural resources, conserve energy, reduce pollution, reduce the toxicity of waste, and save businesses money.Examples of this in the oil and gas industry are effective solids control plans and the reduced amount of Constituents of Potential Concerns (COPCs) used in drilling mud.

Recycling/Composting

This is the EPA’s second most preferred method because it involves taking material that would otherwise be considered waste and converting it into new products. Some of the benefits include: preventing the emission of many greenhouse gases and water pollutants, saving energy, supplying valuable raw materials to industry, conserving resources, and reducing the need for new landfills. An example of recycling in the oil and gas industry is Scott’s Firmus® process. The Firmus® Process takes cuttings from nearby wells and recycles them into useable drilling pads. Using processed drilled cuttings as material for drilling pad construction allows source reduction of virgin material and trucking, and allows for a stronger and more dependable drilling pad in comparison to a traditional location. Another example of recycling is Scott’s Duro(SM) Process which strategically places treated cuttings on pads to provide structural reinforcement.

Energy Recovery

Energy recovery from waste is the conversion of non-recyclable waste materials into useable heat, electricity, or fuel through a variety of processes, including combustion, gasification, pyrolization, anaerobic digestion, and landfill gas (LFG) recovery. This process is often called waste-to-energy (WTE). One example of this in the oil and gas industry is natural gas generators that run off of the natural gas produced during drilling. Another example is thermal desorption. Although thermal desorption removes organic constituents like diesel, it does nothing to remove salts, heavy metals, and other COPCs.

Treatment & Disposal

This is the least preferred method of waste management because it does not allow for any value to be extracted from the material. Treatment comes before disposal to help reduced the toxicity of waste, and/or can take place physically, chemically, and biologically. When it comes to solid waste management there are several examples of treatment and disposal in the oil and gas industry.

Landfills – Although this method of disposal is common throughout the oil and gas industry, it is not without its’ risks and liabilities. Landfills are lined and designed to have several safety checks, but landfills built before 1991 have a history of leaching into the surrounding soil and water tables. Landfills accepting oilfield waste not only pose the threat of leaching, but also release significant amounts of greenhouse gas. This should concern companies looking to implement sustainable practices and reduce pollution.

Land Farming/ Land Spreading – Drilled cuttings contain significant amounts of salts and heavy metals. These constituents prohibit vegetation growth and will not be broken down through bioremediation. These practices leave waste susceptible to runoff and leaching, especially if the waste is spread before a heavy rainstorm. Oil and gas companies incur increased liability when using this method because their waste is contaminating large amounts of land and typically spreads much further than the initial point of application.

Unlined Burial – Unlined burial is the least preferred method because it does not provide a barrier between drilled cuttings and native soil, leaving COPCs to freely leach into the surrounding soil and eventually into the water table. This method leaves oil and gas companies susceptible to substantial fines and carries a concerning amount of risk. Unlined burial is not a sustainable practice.